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wildbillbugman
07-04-2011, 05:44 PM
Hello to All,
I wish to make an emulsion suitable for color separation work. I took a shot of a Kodak chart in mid-day clear sunshine. Bellows factor was 2.3;F11;one second exposure. Developed as usual.

Photo Engineer
07-04-2011, 06:14 PM
Bill;

Your blue speed is way above red. Green is in the middle kinda. In fact, the blue is greatly overexposed I think, compared to the other two.

PE

wildbillbugman
07-04-2011, 06:41 PM
PE,
Do you think that simply uping the dye adition would sufice? I mean, with a fresh batch, not just adding dye to the existing batch..
Bill

Photo Engineer
07-04-2011, 07:24 PM
Yes, it probably would hellp, but remember that sensitizing dyes are also antifoggants and you can therefore lose blue speed and overall contrast.

Nice job with those polymers Bill.

PE

dwross
07-06-2011, 11:04 AM
These balances look really, really close, Bill. I'll have to borrow those night vision goggles of yours and give it a try with gelatin!

Your gray scale looks good (accounting for the variations in density with your coating) and on the second column from the left, at the bottom, the relative values of the magenta and blue look very close. If I had to identify one area that needed work, it might be the greens, but really excellent all-in-all. Congrats! Once you get a coating protocol that is manageable in dead darkness, you'll have it made :).

wildbillbugman
07-06-2011, 01:23 PM
Thanks Denise,
I have read the latest entries on the "Really Large Plates" thread here. I wonder how you controle wet thickness. As I understand it. You position the glass plate in the middle of 4 frame plates, then just cathetor on the emulsion,in the Center, and let it flow out. Are the frame plates higher than the emulsion plate?
All - Triton X-100 appears to eliminate the dewetting of the emulsion on clean glass. I drop for 250g emulsion. This sufactant appears to me to be very effective for PVA based emulsion.
Bill

dwross
07-07-2011, 01:31 PM
Bill,

With a gelatin emulsion, the thickness is controlled by the play between emulsion temp (i.e. viscosity) and the gap distance between the individual plates and dam bars around the perimeter of the plate line-up. I've always used dam bars that are the same thickness as the plates and been fine. The plates are at room temp and by the time the emulsion has spread over the plate and off the edges it has started setting up. I've been getting perfectly even coatings. But...I've been coating formats that are close to square. Michael (studiocarter) is coating elongated rectangles. He's made his dam bars just a tad thicker so that he can pour the emulsion at one end of a plate and then use a straightedge -- riding on the guide bars on each side of the plate -- to push the emulsion down the length of the plate.

Since you aren't working with gelatin, the system might need further tweaking for you. First, your emulsion doesn't 'set up'; it dries, right? What is the viscosity? Is it like cream (that's how I'd describe coating viscosity gelatin emulsions) or like Elmers glue? Either way, I can see that you'd like to have your guide bars thicker than the plates, but also instead of just lining up the plates, you'lll need the thicker glass between them, in effect surrounding each plate, so that your emulsion is dammed at an equal level on all sides. Hope that makes sense.

d

Photo Engineer
07-07-2011, 01:59 PM
Just for reference, one layer of Scotch Tape is about 2.5 mils and of course 2 layers is 5 mils. It does wear fast, but it can give good results providing a gap for coating.

PE

Marco B
07-07-2011, 02:12 PM
Hi Bill,

Really nice seeing you making progress with your experiments.

I know this is not 100% relevant to your work and this thread, but I would like to point out a link to a book I recently discovered. It is a book about coatings applied to photographs. Although this is not like your light sensitive emulsion, since we're talking coating layers applied as protective top layer to developed photos (from the daguerreotype to modern day plastic lamination), the (conservation) research in the book seems very interesting and may give some ideas or be fun to read in the context of your current work:

I referenced it in this thread:
http://www.apug.org/forums/forum205/93165-coating-book.html

Don't forget to have a look at the linked PDF "sneak preview" of one of the chapters as provided by the Albertina Museum. This PDF also contains the Contents section of the book, so you get a better idea of what the book is about.

Marco

dwross
07-07-2011, 02:15 PM
Ron,
That a good tip. It would depend on whether or not you needed a higher-than-the-plate dam (for stopping and set-up, or stopping and drying purposes) but if you just needed a higher surface for the straightedge to ride on, tape would be a dandy way to have just one set of guide bars around.

You can also tape the ends of the straightedge (or puddle pusher type glass rod), of course. Again, depends on the list of emulsion-specific and/or format-specific requirements for the edging glass.

*******************
Marco,
Thanks for that link! I saw it when you first posted and I ordered the book. Very much looking forward to reading it.
d

wildbillbugman
07-07-2011, 09:13 PM
Hi ,
My most recent method was to use an RD Specialties #40 wire rod, wet thickness according to their chart,3.6 mils. I use 2 layers of scotch tape and measure just bairly 8 mills wet thickness. Something made 0.6mils disapear.
Seriously though, I don't have a Brookfield viscometer. But I am absolutely certain that all of these emulsions, gelatin or PVA based, are thixatropic. That is, viscosity ,and therefor rate of flow, are influinced by shear. The faster the draw-down,or the faster the squirt from a syringe, the lower the visositry, and that means more emulsion flowing faster. In the case of PVA based emulsions, there is no thickening due to setting of the emulsion. Therefor the coated emulsion is subject to flowing until the water evaporates.
Bill

Kirk Keyes
07-08-2011, 09:41 AM
Hi ,
Seriously though, I don't have a Brookfield viscometer. But I am absolutely certain that all of these emulsions, gelatin or PVA based, are thixatropic. That is, viscosity ,and therefor rate of flow, are influinced by shear. The faster the draw-down,or the faster the squirt from a syringe, the lower the visositry, and that means more emulsion flowing faster.

Many years ago, I used to use a Brookfield viscometer at work. I don't think it will work well with thixatropic materials. It uses different diameter and shape rods, wheels, and drums to measure the viscosity.

http://www.bcit.ca/files/health/foodproc/img/brookfield_viscometer.jpg

I once had to test blueberry jam with it - it needed a rod that was about 5 mm in diameter for material that viscous. But you would get a much higher reading just after you turn the Brookfield on and a much lower one after a minute or so, as the viscometer wheel would be dragged by the blueberry chunks in the jam at the beginning and then it would pull the thinner jam around it as it spun. I think you would have the same sort of issue with your "emulsion".

(I also had a high viscosity Standard that I used for verifying it's function. It was a silicone "liquid" - you could take the jar and lay it on it's side with the lid off, come back in 30 minutes, and the liquid would just be "pouring" out the bottle. The fun part of this trick was to catch it before it touched the countertop!

But that's a really cool test shot, Bill! I'm looking forward to more photos!

dwross
07-08-2011, 12:12 PM
... In the case of PVA based emulsions, there is no thickening due to setting of the emulsion. Therefor the coated emulsion is subject to flowing until the water evaporates. Bill

It sounds like your emulsion is a perfect candidate for a plate surrounded by thicker dam bars. If you placed all the glass on silicon sheets and pressed them down for really good contact, I'd think the emulsion would stay put long enough to dry nice and even.

I've found this a great silicon sheet: http://www.target.com/gp/detail.html/176-3084851-1770754?asin=B0002MH2HA&AFID=Froogle_df&LNM=|B0002MH2HA&CPNG=kitchen&ci_src=14110944&ci_sku=B0002MH2HA&ref=tgt_adv_XSG10001

wildbillbugman
07-08-2011, 03:41 PM
Yes Denise,
I certainly plan to try it. But that will have to wait until I receive my order of more glass plates. I am down to 8 plates suitable for emulsion plates. I do not use common windowglass. I use Tru-Vue Clear Glass. This is what I use for my finished glass art. It is less green than window glass, but not as expensive as "Iron-Free Water White Glass".
But I think I need a little break now. I tend to work all day and into the next morning. I am feeling a bit exausted. Its the computer and books for me for a couple of days
BTW I strongly recommend Tru-Vue for anyone who pants to print anything on glass. There is a regular dealer on ebay who sells several types a very reasonable prices.
Yes,Kirk
I too have experience with Brookfields. Even without chunks of blueberries, a homogenous thixotropic liquid, such as various types of traditional printing inks, will start off with a higher reading. Given a constant temperature a reading will decrease until it reaches a constant for a given rate of shear. Increase the shear (higher RPM) and. in a thixotropic liquid, the viscosity reading will fall.
Bill

wildbillbugman
07-13-2011, 01:00 PM
My little vacation is extended a bit. I am now holding off until I receive more of the R-Polymer. I am out now.
B&S has indicated that they will be ordering a 20kg sack. That is the Kuraray minimum order . So, if anyone is interested in giving it a try, Kuraray will send you a pound for free. But it looks like it will be availible from B&S. 20 kg is a bit too much to have laying around.
Bill

holmburgers
07-20-2011, 03:40 PM
Do you think that this polymer stuff would imbibe dyes? Would it stick to completely raw (unsubbed) melinex?

The reason I ask is, if you could coat a layer of this polymer, and have it not lift off of unsubbed melinex, you could then coat a gelatin emulsion for subsequent sensitization and etching using the carbon method. However, it should not be able to imbibe the acid dyes used in dye-transfer processes or else you can't really get clean & clear highlights.

PhotoFormulary has a subbed melinex which is awesome, but I understand it's a somewhat limited supply and who doesn't like an alternative?

Just a thought!

wildbillbugman
07-21-2011, 12:22 AM
I do not think that the R-Polymer would adhere to melanex. The Silane functionality works only for glass and other Si containing surfaces. Dave Pitcher has tried it on Plexiglas with, I think, little success. Kuraray dose make an anionic and a cationic functional PVA.

dyetransfer
07-22-2011, 01:45 PM
Do you think that this polymer stuff would imbibe dyes? Would it stick to completely raw (unsubbed) melinex?

The reason I ask is, if you could coat a layer of this polymer, and have it not lift off of unsubbed melinex, you could then coat a gelatin emulsion for subsequent sensitization and etching using the carbon method. However, it should not be able to imbibe the acid dyes used in dye-transfer processes or else you can't really get clean & clear highlights.

PhotoFormulary has a subbed melinex which is awesome, but I understand it's a somewhat limited supply and who doesn't like an alternative?

Just a thought!

You should try coating unsubbed polyester with a very thin (diluted) coating of Shellac. The solvent is Ethanol. I'm not sure how well it will coat on raw polyester, but it is worth a try. I do know that it works as a subbing layer, will adhere to polyester well, doesn't pickup any dye, and will hold gelatin quite strongly. You could probably get a print coating machine (used in photolabs) to coat sheets of polyester. I think these machines are used with solvent based coating materials. This would be used as a subbing layer, specifically for Matrix film use.

Regards - Jim Browning

DPVisions
07-22-2011, 10:42 PM
I do not think that the R-Polymer would adhere to melanex. The Silane functionality works only for glass and other Si containing surfaces. Dave Pitcher has tried it on Plexiglas with, I think, little success. Kuraray dose make an anionic and a cationic functional PVA.

I have tried without success of having PVOH polymer, both the Kuraray R-1130 and Poval 217, work well as a coating onto plexiglass. Coating is easy and when dried is hard and adheres well. Once in gets in contact with water again it will float and/or peel off. Both polymers need heat to cure and become insoluable in water and heat required is not good for plexiglass.

As Bill pointed out you can get use one of the anionic polmers such as KL-318 and it will hold strong onto polyester but is still water soluable and will disolve unless crosslinked or heat cured.

Polyvinyl butyral(PVB) works as a subbing agent for plexiglass, PET, PETG, and is only soluable in strong solvents, such as ethanol. Never tested to see how well a gelatin size/emulsion adheres since my experimentation has around removing gelatin from the equation.

Cheers,
David